Best 24 inch kids mountain bikes

Twenty-four inches is where kids mountain bikes become real bikes — discs, gears and suspension forks all appear here. It is also where the weight problem bites hardest, because a coil fork on a child sized bike can add five to ten pounds to a machine a 60 lb rider has to pedal uphill. Buy the lightest bike that has the brakes you need, and treat suspension as optional.

What to look for in a 24-inch kids mountain bike

Weight, before anything else

The CDC median nine-year-old weighs about 63.2 lb. A 20.75 lb woom EXPLORE 5 is roughly 33 percent of that child; a 30.6 lb Dart Plus 24 is about 48 percent. Scaled onto a 180 lb adult, that is a 59 lb bike against a 86 lb one.

Adults do ride 55 lb bikes. They do not ride them up hills for fun, and neither will a nine-year-old. On trails the heavier bike costs you range, which is the thing that decides whether your child wants to come out again next weekend.

Suspension that actually does something

A coil fork needs the rider's weight to compress it. A 60 lb child on a fork sprung for a much heavier rider gets a rigid fork that weighs five pounds more than a rigid fork. Before you pay for suspension, watch where the bike will actually be ridden — gravel paths and school runs do not need it, rooty singletrack does.

Brakes that work in the wet

Discs are the real upgrade at this size, more so than the fork. The EXPLORE 5 uses Promax hydraulic flat-mount discs, which need far less hand strength than a V-brake; the Dart Plus uses 160 mm Tektro mechanicals, which are heavier and need more lever force but still out-perform rim brakes on a muddy descent.

Gearing you can shift under load

All four bikes here are geared. The difference is the shifter: the woom uses a microSHIFT Acolyte trigger, the others use twist grips. A trigger is easier to use accurately with cold or tired hands, which on a trail is most of the ride. More on when gears start earning their keep is on when do kids need gears.

The fit spread at 24 inch is enormous

Retrospec publishes a 23.5 inch minimum saddle for the Dart 24. woom needs a 26.4 inch inseam for the EXPLORE 5. That is nearly three inches between two bikes with the same wheel diameter, and it is more than a year of growth at this age. A child who fits one may not fit the other, so the fit column in the table above is doing more work than the price.

Mongoose publishes no fit figures at all for the Flatrock 24, which is why it sits third here despite having the most travel. Buying a bike you cannot size is a gamble you do not need to take.

The picks

woom EXPLORE 5 — the one to buy

20.75 lb, hydraulic discs front and rear, eight gears with a trigger shifter, and a published 26.4 to 32.3 inch inseam range. Rigid fork. On everything except technical descents, the ten pounds it saves does more for a child's riding than any fork at this price could.

Retrospec Dart Plus 24 — real trail hardware on a budget

30.6 lb with 160 mm Tektro mechanical discs, a 50 mm coil fork and a published 26 to 32.5 inch saddle range. If your child is riding actual singletrack and the budget will not stretch to a specialist brand, this is the honest pick — just go in knowing the weight.

Mongoose Flatrock 24 — the most travel

An aluminum frame with a 60 mm Element suspension fork and a 1x7 drivetrain, on V-brakes rather than discs. The most fork travel here and the only aluminum frame among the budget bikes, but Mongoose publishes neither a weight nor a saddle range.

Retrospec Dart 24 — rigid, lighter, cheaper

28.25 lb, rigid fork, alloy V-brakes and a 23.5 to 29 inch saddle range — the lowest floor on this page, so it fits smaller riders than the others. If the trails are mild, dropping the fork saves weight and money at the same time.

For mountain bikes across every wheel size rather than just 24 inch, see best kids mountain bikes. For non-trail 24-inch bikes, the general roundup is best 24 inch kids bikes.

Setting a 24-inch trail bike up for a child

Protective gear matters more at this size than at any earlier one, because the speeds are real. Knee pads a child will actually keep on for a whole ride are on best kids knee pads.

What a 24-inch trail bike does not need

Rear suspension. Full-suspension kids bikes exist and almost none of them make sense: the weight penalty is severe on a rider who weighs sixty pounds, and the shock is sprung for a load the child does not apply. A hardtail with a fork that actually moves is a better bike in every practical sense at this size.

A wide-range cassette, too. Seven or eight gears with a sensible spread covers everything a child at this size will ride. More sprockets add weight, cost and shifting that goes out of adjustment, and the child is not running out of gears — they are running out of legs.